1997 GMC Savana Van Owner's Manual - Page 76

Both rear doors can be opened past90 degrees by opening the doors past the first detent (90 degrees open), then opening fully. To close the rear doors, close the driver side reardoor first. Then, close the passenger side rear door. Check to make sure both doors arecompletely closed. It can be dangerous to drive with the rear doors open becausecarbon monoxide (CO) gas can come into your vehicle. You can't see or smell CO. It can cause unconsciousness and even death. CAUTION: (Continued) If you must drive with the rear doors open or if electrical wiring or other cable connections must pass through the seal between the body and the rear doors: 0 Make sure all windows are shut. 0 Turn the fan on your heating or cooling system to itshighest speed with setting the on VENT, HEAT, BLEND DEF. or Additionally, on vehicles with heatingair conditioning systems, NORM A/C or BI-LEV A/C can be used. That will force outside air into your vehicle. See"Comfort Controls" in the Index. 0 If you have air outlets on or under the instrument panel, openthem all the way. See "EngineExhaust" in the Index. 2-14